1. Electroarthrography: a novel method to assess articular cartilage and diagnose osteoarthritis by non-invasive measurement of load-induced electrical potentials at the surface of the knee 
A.-M. Préville, P. Lavigne, M.D. Buschmann, J. Hardin, Q. Han, L. Djerroud, P. Savard 
Osteoarthritis and Cartilage 
Volume 21, Issue 11, Pages (November 2013)
DOI: /j.joca
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2. Fig. 1
Positioning of the eight electrodes: on the medial side, two electrodes (#2 and 3) were placed over the joint line determined by palpation, another electrode was placed above (#1) and a final (#4) below these first two electrodes; electrode placement was similar on the lateral side (note that the lateral joint line may not be at the same height as that on the medial side).
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
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3. Fig. 2
Example low-pass filtered (5 Hz) EAG signals recorded at the eight electrode sites along with the inclinometer signal (bottom) from a Control subject who repeatedly shifted his weight from one leg to the other. A positive displacement for the inclinometer signal corresponds to the loading of the knee. During a 60 s interval, six compression cycles produced six positive rectangular pulses for all electrode sites, with the highest potential shifts at site 2 (0.3–0.4 mV). The vertical scale is 0.75 mV for the EAG.
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
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4. Fig. 3
Mean potential values (±95% confidence interval) at the eight electrode sites for the Control group (N = 20), the intact knee of the osteoarthritis group (N = 20) and over the knee prosthesis of the same OA patients. P-values: ** for P < 0.01, * for P < 0.05.
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
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5. Fig. 4
Finite element mesh for an electrostatic knee model (left) and simulated electric potential distribution over the knee surface (right). The simulated potential distribution is represented with an isopotential map: regions with the same color have the same potential with respect to the reference electrode, with increasing potential from blue (minimum: −0.09 mV) to red (maximum: +0.29 mV), which shows the same site of maximum potential (arrow) over the joint line as that measured in the Control subjects (electrode #2).
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
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